Cartridge ignition system

ABSTRACT

A rim-fire ignition system in which a ring-type primer is provided in an annular receptacle adjacent the periphery of the rearward end of the large caliber cartridge case. The primer is an annulus of extruded ignition material and preferably includes an extruded aluminum sheath surrounding a fixed core load of priming mixture that can be ignited by an offset firing mechanism. The arrangement assures good quality control of the primer charge weight from cartridge to cartridge.

United States Patent 1191 C iccone et a1.

[ 1 Jan. 22, 1974 CARTRIDGE IGNITION SYSTEM Inventors: Thomas Q.Ciccone, Comwells Heights; George F. Hare, Feasterville; OsypNimylowycz, Philadelphia, all of Pa.

The United States of America as represented by the Secretary of theArmy, Washington, DC.

Filed: June 28, 1972 Appl. No.: 266,956

Assignee:

US. Cl. 102/45, 102/44 lint. Cl F42b 5/32, F42b 5/36, F42c 19/10 Fieldof Search... 102/45, 44, 43 R, 38, 39, 40,

References Cited UNITED STATES PATENTS 2/1910 Dorn .L 102/38 PrimaryExaminer-Robert F. Stahl Attorney, Agent, or Firm-Edward J. Kelly;Herbert Berl; William Sommer [57] ABSTRACT A rim-fire ignition system inwhich a ring-type primer is provided in an annular receptacle adjacentthe periphery of the rearward end of the large caliber cartridge case.The primer is an annulus of extruded ignition material and preferablyincludes an extruded aluminum sheath surrounding a fixed core load ofpriming mixture that can be ignited by an offset firing mechanism.

The arrangement assures good quality control of the primer charge weightfrom cartridge to cartridge.

3 Claims, 4 Drawing Figures CARTRIDGE IGNITION SYSTEM The inventiondescribed herein may be manufactured, used, and licensed by or for thegovernment for governmental purposes without the payment to us of anyroyalty thereon.

This invention relates to cartridges and, more particularly, tocartridge ignition systems.

Previous endeavors to employ rim-fire cartridges in larger caliberammunition have presented several problems, notably the difficulty incontrolling the weight of the priming mixture that heretofore had filledits cavity via spinning techniques.

It is an object of the invention to provide a large caliber cartridgeignition system which has good quality control of the priming mixtureweight.

Another object of the invention is to provide such a system that permitslocation of the firing pin in any possible axially offset position inthe face of the gun breech.

These and other objects, features and advantages will become apparentfrom the following description and accompanying drawings in which:

FIG. 1 is a longitudinal sectional view of a preferred cartridgeignition arrangement embodying the principles of the invention.

FIG. 2 is an enlarged sectional view of the primer construction in theFIG. 1 arrangement.

FIG. 3 is a sectional view taken along line 3--3 of FIG. 2.

FIG. 4 is a longitudinal sectional view of a modified cartridge ignitionsystem.

In a preferred cartridge ignition system the cartridge case (FIG. 1) hasa closed rearward base or end wall 11, the interior surface 12 of whichpartially defines the propellant chamber 13 which contains anappropriate munition propellant 14 to fire a projectile (not shown)which is normally secured at the forward end of the cartridge. At apredetermined location in the rearward surface of base 11, preferablyadjacent the radial periphery thereof there is provided a rearwardlyopening circular groove 16 of substantially rectangular crosssectionalconfiguration. The base of the groove 16 has an annular rib orprotuberance 17 for a purpose to be described. A longitudinal ventpassage 18 through the base 1111 and rib 17 places the ring-shapedgroove 16 in fluidcommunication with propellant charge 14.

A ring-type primer housing 20 (FIGS. ll, 2), that has a substantiallyU-shaped cross-section terminating in circular free end portions 21 and22 (FIGS. 2, 3), press-fittingly receives a predetermined length ofextruded primer ignition material 23 which is formed of an extrudedaluminum or other metal sheath surrounding a fixed core load of primingmixture 24. The length of primer material 23 is selected so as tosubstantially fill housing 20 with an annular shaped primer, thecross-section of which is initially substantially circular, with theprimer core preferably being of circular crosssection also.

When the primer contained housing 20 is pressed or seated into the basegroove 16, the primer annulus 23 is deformed and the primer core is bothdeformed slightly and sensitized by the annular rib 17 which the primerannulus 23 abuts and preferably surrounds upon deformation. Apredeterminedly positioned firing pin mechanism (not shown) can thuspenetrate and ignite the primer from an axially offset location,regardless of the rotational position of the cartridge case relative tothe barrel or weapon breech. The corresponding diametric dimensions ofthe primer housing and base groove can be varied, so long as the firingpin is arranged to strike along an axis that contains the primer core.

In the modification of FIG. 4, the cartridge ignition system issubstantially limited to a rim-fire functioning. The cartridge case 30has a ring-shaped receptacle 32 formed at the juncture of the case thinrearward end 31 and the sidewall of the cartridge case. The formedreceptacle 32 has a diameter greater than that of the case sidewall suchthat a predetermined length of primer material 23 can be pressed into orfitted to substantially fill the receptacle 32, prior to loading of thepropellant charge 14 and securing a suitable projectile (not shown) inthe forward end of the cartridge. An appropriate firing pin mechanismcan be positioned to strike a predetermined peripheral wall portion ofthe thinwalled receptacle 32 to ignite the primer mix core 24 andpropellant charge surrounding the primer annulus 23 to rim-fire theround of ammunition.

Various modifications, changes or alterations may be resorted to withoutdeparting from the scope of the invention as defined in the appendedclaims.

We claim:

1. In a cartridge case having a propellant chamber containing propellantfor firing a projectile, said case having a closed rearward end defininga portion of said propellant chamber,

said case rearward end having an annular receptacle,

and

a primer annulus of extruded ignition material located in said annularreceptacle adjacent a substantially peripheral portion of said caserearward end, said primer annulus including an extruded aluminum sheathsurrounding a core of priming mixture, so constructed and arranged thatan offset firing mechanism can ignite said primer annulus.

2. The structure of claim 1 wherein said case rearward end has arearwardly opening circular groove, the base of said groove having anannular protuberance and a vent passage fluidly communicating saidgroove with said propellant chamber, and said annular receptacle is aring-type primer housing containing said primer annulus and seated insaid groove with said primer annulus in abutment with said protuberance.

3. The structure of claim I wherein said cartridge case includes asidewall, the annular receptacle is a ring-shaped receptacle at thejuncture of said case rearward end and the sidewall of said case, saidring-shaped receptacle having a diameter larger than the diameter ofsaid case sidewall, and said primer annulus being positioned within saidring-shaped receptacle.

1. In a cartridge case having a propellant chamber containing propellantfor firing a projectile, said case having a closed rearward end defininga portion of said propellant chamber, said case rearward end having anannular receptacle, and a primer annulus of extruded ignition materiallocated in said annular receptacle adjacent a substantially peripheralportion of said case rearward end, said primer annulus including anextruded aluminum sheath surrounding a core of priming mixture, soconstructed and arranged that an offset firing mechanism can ignite saidprimer annulus.
 2. The structure of claim 1 wherein said case rearwardend has a rearwardly opening circular groove, the base of said groovehaving an annular protuberance and a vent passage fluidly communicatingsaid groove with said propellant chamber, and said annular receptacle isa ring-type primer housing containing said primer annulus and seated insaid groove with said primer annulus in abutment with said protuberance.3. The structure of claim 1 wherein said cartridge case includes asidewall, the annular receptacle is a ring-shaped receptacle at thejuncture of said case rearward end and the sidewall of said case, saidring-shaped receptacle having a diameter larger than the diameter ofsaid case sidewall, and said primer annulus being positioned within saidring-shaped receptacle.